This invention relates to butadienes substituted on each of their four carbon atoms by a C.sub.1 -C.sub.10 perfluoroalkyl group. These novel tetrakis(perfluoroalkyl)butadienes have utility as transporters of dissolved gas, in particular of oxygen and carbon dioxide. This property makes them especially useful as new substitutes for red blood corpuscles in a physiological technology illustrated by H. A. Sloviter and T. Kamimoto (Nature 216 458 (1967)) and R. P. Geyer (Federation Proceedings 27 952 (1968)) who have prepared emulsions of oxygen-dissolving fluorinated compounds in aqueous physiological saline solution which can be partially or completely exchanged for the blood of mice and dogs.
Fluorinated butadienes are known having the structure CX.sub.2 =CX--CX=CX.sub.2 where X is hydrogen or halogen. See R. A. Mitsch and E. W. Neuvar, J. Phys.Chem. 70 (2) 546-553 (1966) also G. Camaggi et al, Tetrahedron 22 (6) 1755-63 (1966).
As to perfluoroalkyl butadienes, mono-substituted derivatives having just one perfluoralkyl group are described in French Pat. Nos. 1,361,255 and 1,361,256, also in U.S. Pat. Nos. 2,945,896 and 2,490,753. Also, bis-perfluoroalkyl butadienes are disclosed in U.S. Pat. No. 3,035,034 and by M. H. Kaufman, J. Polymer-Sci., AI 10 (1971) 455-464 and by P. Tarrant J. Org. Chem. 24 (1959) 1888 and 25 (1960) 2254.
However, to the best knowledge of present applicants, tris and tetrakis(perfluoroalkyl)butadienes have not been specifically described with the exception of fluorinated cyclic products typified by perfluorobicyclo-1, 1'-pentenyl as reported by Camaggi in J. Chem. Soc. (C) (1971) 2382 and Tetrahedron 22 (1966) 1758. Indeed, British Pat. No. 774,103 recites a generalized formula (FIG. 7 on page 7 thereof) ##STR1## WHEREIN THE SYMBOLS R.sub.u to R.sub.z are stated to be "appropriately selected to represent hydrogen, halogen, alkyl and halogenoalkyl groups". But a careful reading of this patent reveals no description of any compound having as in the present application R.sub.u = R.sub.y = H and R.sub.v, R.sub.w, R.sub.x, and R.sub.z all equal to C.sub.1 -C.sub.10 perfluoroalkyl groups. In fact, no preparations are described which would give an art-skilled person any confidence that the synthetic method of that patent could be adapted to prepare tetrakis-(perfluoroalkyl) products satisfactorily and in good yield. Also the specialized gas-transporting properties of the compounds of the instant invention are not recognized by the British patent.
The method of forming halogenated dienes according to British Pat. No. 774,103, involves a cumbersome succession of steps including the intermolecular deiodination of a saturated compound having a chlorine on the same carbon as the iodine and either hydrogen or chlorine on the carbon adjacent thereto, followed by either dehydrochlorination of dechlorination, as the case may be, to form the desired twofold unsaturation.
Thus, if such a method were attempted to form the compounds of the instant invention, it would be necessary to have as starting materials saturated iodides of the formula ##STR2## wherein n and m have the same meaning as above described.
Reductive coupling of such compounds would then lead to fully saturated products which would subsequently have to be dehydrochlorinated or dechlorinated respectively to yield the desired dienes. The magnitude of the yields to be expected are of course, unknown - but even if acceptable yields could be obtained the plurality of steps required would be burdensome and costly.